ajaxFileUpload插件，C#返回Json数据报错问题的解决方案

 handleError: function(s, xhr, status, e) {
  // If a local callback was specified, fire it 
  if (s.error) {
   s.error.call(s.context || s, xhr, status, e);
  }
  // Fire the global callback 
  if (s.global) {
   (s.context ? jQuery(s.context) : jQuery.event).trigger("ajaxError", [xhr, s, e]);
  }
 },

function FileUpload() {
 $.ajaxFileUpload({
  url: '/Common/Image',
  fileElementId: 'upload_img',
  dataType: 'content',//此处写content，是因为想让ajaxFileUpload直接return data数据，即带<pre>标签的数据。
  success: function(data) {
   var reg = /<pre.+?>(.+)<\/pre>/g;
   var result = data.match(reg);
   data = RegExp.$1;
   var obj = eval("data=" + data); //转josn
   if (obj.error == 1) {
    $("#images_src").attr("src", obj.msg);
    $("#img_path").val(obj.msg);
   } else {
    alert("失败");
   }

  },
  error: function(data, status, e) {
   alert(e);
  }
 });
 return false;
}

uploadHttpData: function(r, type) {
 var data = !type;
 data = type == "xml" || data ? r.responseXML : r.responseText;
 // If the type is "script", eval it in global context
 if (type == "script")
  jQuery.globalEval(data);
 // Get the JavaScript object, if JSON is used.
 if (type == "json")
  eval("data = " + data);
 // evaluate scripts within html
 if (type == "html")
  jQuery("<div>").html(data).evalScripts();
 //此处是去掉<pre>标签的代码，新添加一种类型，前台js的dataType类型写content，即dataType: 'content'
 if (type == "content") {
  var reg = /<pre.+?>(.+)<\/pre>/g;
  var result = data.match(reg);
  data = RegExp.$1;
  eval("data = " + data);
 }
 return data;
}

uploadHttpData: function(r, type) {
 var data = !type;
 data = type == "xml" || data ? r.responseXML : r.responseText;
 // If the type is "script", eval it in global context
 if (type == "script")
  jQuery.globalEval(data);
 // Get the JavaScript object, if JSON is used.
 if (type == "json")
  eval("data = " + data);
 // evaluate scripts within html
 if (type == "html")
  jQuery("<div>").html(data).evalScripts();
 //此处是去掉<pre>标签的代码
 if (type == "content") {
　　　　 //------以下是修改的代码------
  var start = data.indexOf(">");
  if (start != -1) {
   var end = data.indexOf("<", start + 1);
   if (end != -1) {
    data = data.substring(start + 1, end);
   }
  }
  eval("data = " + data);
 }
 return data;
}

var start = data.indexOf("{");
if (start != -1) {
 var end = data.indexOf("}", start + 1);
 if (end != -1) {
  data = data.substring(start + 1, end);
 }
}